#include<bits/stdc++.h>
#define ll long long
#define ull unsigned long long
using namespace std;

const int N = 1e6 + 10, INF = 0x3f3f3f3f;

int n;
int a[N], s[N];

void solve()
{
    cin >> n;
    for (int i = 1;i <= n;i++) {
        cin >> a[i];
        s[i] = s[i - 1] ^ a[i];
    }

    int ans = 0;
    for (int i = 1;i < n;i++)
        ans = max(ans, s[i] & (s[n] ^ s[i]));

    ans = max(ans, s[n]);

    cout << ans << '\n';
}

signed main()
{
    //ios::sync_with_stdio(0);
    //cin.tie(0);cout.tie(0);
#define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
    std::istringstream in(R"()");
    std::cin.rdbuf(in.rdbuf());
#endif
    int T = 1;
    cin >> T;
    for (int i = 1;i <= T;i++) {
        solve();
    }
}